update_ip: add offline check, for my faulty wireless card

update_ip.sh

@@ -1,11 +1,19 @@
 #!/bin/sh
 
+ping -qc 1 "${server}" > /dev/null
+if [ ${?} != 0 ]; then
+  # We are offline
+  exit
+fi
+
 cache=.update_ip.cache
 server=ns1.example.com
 zone=dyn.example.com
 host=desktop
 secret=""
-iface=$( ip route get $( dig +short ${server} | grep [0-9] ) | grep -Po '(?<=(dev ))(\S+)' )
+
+server_ip=$( dig +short ${server} | grep [0-9] | head -1 )
+iface=$( ip route get ${server_ip} | grep -Po '(?<=(dev ))(\S+)' )
 
 # TODO trigger not via cron, but using ip monitor in a while/sleep loop:
 #ip monitor address dev ${iface} | while read event; do